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Fair Value Measurements - Impaired Loans Remeasured and Reported at Fair Value of Underlying Collateral (Detail) - USD ($) $ in Thousands	Mar. 31, 2021	Mar. 31, 2020
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying value of impaired loans before allocations	$ 100	$ 1,919
Impaired Financing Receivable, Specific Valuation Allowance Allocation	0
Impaired Financing Receivable, Reversal of Specific Valuation Allowance Allocations		70
Loans receivable, fair value disclosure	100	1,989
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying value of impaired loans before allocations	15,013	3,867
Impaired Financing Receivable, Specific Valuation Allowance Allocation		(244)
Impaired Financing Receivable, Reversal of Specific Valuation Allowance Allocations	600
Loans receivable, fair value disclosure	$ 15,613	$ 3,623

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Impaired Financing Receivable, Reversal of Specific Valuation Allowance Allocations

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Amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 14A
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121611835&loc=SL6953550-111524

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Amount of allowance for credit losses related to recorded investment.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (a)(3)
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Fair value portion of loan receivable, including, but not limited to, mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-URI http://asc.fasb.org/subtopic&trid=2196772

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